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111.
112.
Durum wheat mitochondria (DWM) possess an ATP-inhibited K(+) channel, the plant mitoK(ATP) (PmitoK(ATP) ), which is activated under environmental stress to control mitochondrial ROS production. To do this, PmitoK(ATP) collapses membrane potential (ΔΨ), thus suggesting mitochondrial uncoupling. We tested this point by studying oxidative phosphorylation (OXPHOS) in DWM purified from control seedlings and from seedlings subjected both to severe mannitol and NaCl stress. In severely-stressed DWM, the ATP synthesis via OXPHOS, continuously monitored by a spectrophotometric assay, was about 90% inhibited when the PmitoK(ATP) was activated by KCl. Contrarily, in control DWM, although PmitoK(ATP) collapsed ΔΨ, ATP synthesis, as well as coupling [respiratory control (RC) ratio and ratio between phosphorylated ADP and reduced oxygen (ADP/O)] checked by oxygen uptake experiments, were unaffected. We suggest that PmitoK(ATP) may play an important defensive role at the onset of the environmental/oxidative stress by preserving energy in a crucial moment for cell and mitochondrial bioenergetics. Consistently, under moderate mannitol stress, miming an early stress condition, the channel may efficiently control reactive oxygen species (ROS) generation (about 35-fold from fully open to closed state) without impairing ATP synthesis. Anyway, if the stress significantly proceeds, the PmitoK(ATP) becomes fully activated by decrease of ATP concentration (25-40%) and increase of activators [free fatty acids (FFAs) and superoxide anion], thus impairing ATP synthesis. 相似文献
113.
Malaspina TS Gasparoto TH Costa MR de Melo EF Ikoma MR Damante JH Cavassani KA Garlet GP da Silva JS Campanelli AP 《Cancer immunology, immunotherapy : CII》2011,60(7):965-974
PD-1 and PD-L1 can be involved in tumor escape, and little is known about the role of these molecules in oral tumors or pre-malignant
lesions. In the present study, we investigated the expression of PD-1 and PD-L1 in the blood and lesion samples of patients
with actinic cheilitis (AC) and oral squamous cell carcinoma (OSCC). Our results showed that lymphocytes from peripheral blood
and tissue samples exhibited high expression of PD-1 in both groups analyzed. Patients with AC presented higher percentage
as well as the absolute numbers of CD4+PD-1+ and CD8+PD-1+ lymphocytes in peripheral blood mononuclear cells (PBMC) than healthy individuals, while patients with OSCC presented an
increased frequency of CD8+PD1+ in PBMC when compared with controls. On the other hand, increased frequency of CD4+ and CD8+ T cells expressing PD-1+ accumulate in samples from OSCC, and the expression of PD-L1 was intense in OSCC and moderate in AC lesion sites. Lower levels
of IFN-γ and higher levels of TGF-β were detected in OSCC samples. Our data demonstrate that PD-1 and PD-L1 molecules are
present in blood and samples of AC and OSCC patients. Further studies are required to understand the significance of PD-1
and PD-L1 in oral tumors microenvironment. 相似文献
114.
Antibiotic-resistant bacteria are an increasing source of concern in all environments in which these drugs have been used.
More stringent regulations have led to a slow but sure decrease in antibiotic use in the food industry worldwide, but have
also stimulated the search for alternative antibacterial agents. In medicine, the number of people infected with pan-resistant
bacteria is driving research to develop new treatments. Within these contexts, studies on the use of bacteriophages in both
medicine and the food industry have recently flourished. This renewed interest has coincided with the demonstration that these
viruses are involved in geochemical cycles, revolutionizing our vision of their ecological role on our planet. Bacteriophages
have co-evolved with bacteria for billions of years and retain the ability to infect bacteria efficiently. They are undoubtedly
one of the best potential sources of new solutions for the management of undesirable bacteria. 相似文献
115.
Tallita C.L. Tavares Vanessa L.R. Nogueira Ilka M. Vasconcelos Maura da Cunha Vânia M.M. Melo 《Journal of experimental marine biology and ecology》2011,407(2):200-206
Sea hares are well known, nearly shell-less, marine opisthobranchs that use a complex repertoire of chemicals for defense and communication instead of a conventional gastropod shell. The most conspicuous characteristic of these invertebrates is the secretion of ink, which is rich in bioactive proteins. Many of these proteins belong to a family of L-amino acid oxidases (L-AAOs). In the current study, we aimed to determine whether dactylomelin-P, an antibacterial protein isolated from the ink of Aplysia dactylomela, could act as an L-AAO. We also investigated its biochemical properties and antibacterial mechanism of action. We found that dactylomelin-P is an acidic protein (pI = 5.0), rich in glutamic acid/glutamine, aspartic acid/asparagine, tyrosine, serine, and proline. It was stable under a broad pH range (3.0-12.0), after heating to 55 °C for 30 min, and after treating with protease. Its N-terminal amino acid sequence was DGVCSNRRQCNKEVCGSSYDVAIVGA and showed high similarity to other sea hare proteins previously identified as L-AAOs. The L-AAO activity was confirmed in an enzymatic assay, which showed that dactylomelin-P could oxidize L-lysine and L-arginine. We also demonstrated that the bacteriostatic activity of dactylomelin-P was mediated by hydrogen peroxide generated in the enzymatic reaction, but it acted as a bactericide in the presence of L-lysine and L-arginine. Transmission electron microscopy analyses showed that dactylomelin-P bound to growth-phase bacteria without causing morphological alterations to the cells. The bactericidal effect seems to involve H2O2 and other reactive components since it was not counteracted by H2O2 scavengers. Our findings showed biochemical, functional, and phylogenetic similarities among L-AAOs isolated from sea hares; this offers new insight into the evolution of these proteins and their roles in chemical defense. 相似文献
116.
117.
Ray Gervacio F. Blanco Joseph Califano Barbara Messing Jeremy Richmon Jia Liu Harry Quon Geoffrey Neuner John Saunders Patrick K. Ha Sheila Sheth Maura Gillison Carole Fakhry 《PloS one》2014,9(1)
Background
Base of tongue (BOT) is a difficult subsite to examine clinically and radiographically. Yet, anatomic delineation of the primary tumor site, its extension to adjacent sites or across midline, and endophytic vs. exophytic extent are important characteristics for staging and treatment planning. We hypothesized that ultrasound could be used to visualize and describe BOT tumors.Methods
Transcervical ultrasound was performed using a standardized protocol in cases and controls. Cases had suspected or confirmed BOT malignancy. Controls were healthy individuals without known malignancy.Results
100% of BOT tumors were visualized. On ultrasound BOT tumors were hypoechoic (90.9%) with irregular margins (95.5%). Ultrasound could be used to characterize adjacent site involvement, midline extent, and endophytic extent, and visualize the lingual artery. No tumors were suspected for controls.Conclusions
Ultrasonography can be used to transcervically visualize BOT tumors and provides clinically relevant characteristics that may not otherwise be appreciable. 相似文献118.
Tomohiro Komorita Rumiko Kajihara Hiroaki Tsutsumi Seiichiro Shibanuma Toshiro Yamada Shigeru Montani 《PloS one》2014,9(1)
The relationship between the food demand of a clam population (Ruditapes philippinarum (Adams & Reeve 1850)) and the isotopic contributions of potential food sources (phytoplankton, benthic diatoms, and organic matter derived from the sediment surface, seagrass, and seaweeds) to the clam diet were investigated. In particular, we investigated the manner in which dense patches of clams with high secondary productivity are sustained in a coastal lagoon ecosystem (Hichirippu Lagoon) in Hokkaido, Japan. Clam feeding behavior should affect material circulation in this lagoon owing to their high secondary productivity (ca. 130 g C m−2 yr−1). Phytoplankton were initially found to constitute 14–77% of the clam diet, although phytoplankton nitrogen content (1.79–4.48 kmol N) and the food demand of the clam (16.2 kmol N d–1) suggest that phytoplankton can constitute only up to 28% of clam dietary demands. However, use of isotopic signatures alone may be misleading. For example, the contribution of microphytobenthos (MPB) were estimated to be 0–68% on the basis of isotopic signatures but was subsequently shown to be 35±13% (mean ± S.D.) and 64±4% (mean ± S.D.) on the basis of phytoplankton biomass and clam food demand respectively, suggesting that MPB are the primary food source for clams. Thus, in the present study, the abundant MPB in the subtidal area appear to be a key food source for clams, suggesting that these MPB may sustain the high secondary production of the clam. 相似文献
119.
120.
Valeria Aguilera Luis Brice?o Hector Contreras Liliana Lamperti Esperanza Sepúlveda Francisca Díaz-Perez Marcelo León Carlos Veas Rafael Maura Jorge Roberto Toledo Paulina Fernández Ambart Covarrubias Felipe Andrés Zu?iga Claudia Radojkovic Carlos Escudero Claudio Aguayo 《PloS one》2014,9(11)